NLRP3 targets HMGB1 to exacerbate the pyroptosis of canine corneal epithelial cells infected with Staphylococcus pseudintermedius.

PURPOSE: This study focused on the mechanisms of pyroptosis and oxidative damage exacerbation by NOD-like receptor thermal protein domain associated protein 3 (NLRP3) during the infection of canine corneal epithelial cells (CCECs) with Staphylococcus pseudintermedius.

METHODS

The CCECs treated with dimethyl fumarate (DMF), recombinant high mobility group protein 1 (HMGB1), or N-acetylcysteine (NAC). The gasdermin (GSDM) family and HMGB1 mRNA expression levels were detected using quantitative reverse transcription polymerase chain reaction. Lactate dehydrogenase activity, bacterial counts, the pyroptosis rate, reactive oxygen species (ROS) content, and antioxidant enzyme activity were used to reflect pyroptosis and oxidation level.

RESULTS

Regulation of NLRP3 significantly affected the pyroptosis rate and GSDMD-N expression levels during S. pseudintermedius infection. Inhibition of GSDMD-N protein activation by DMF reversed the exacerbation of pyroptosis induced by NLRP3 overexpression and reduced the levels of cleaved interleukin-1β (IL-1β), cleaved cysteinyl aspartate-specific protease-1, and NLRP3. In addition, NLRP3 was found to target the HMGB1 promoter and regulate its protein expression, to increase ROS accumulation and GSDMD-N expression levels, and activate the NLRP3-HMGB1-ROS-GSDMD signaling axis to aggravate pyroptosis during infection.

CONCLUSIONS

NLRP3 aggravates pyroptosis and oxidative damage associated with the activation of NLRP3-GSDMD and NLRP3-HMGB1-ROS-GSDMD signaling pathways during the infection of CCECs with S. pseudintermedius.